Prepare objects made of various materials: wood, metal, clay, plastic, paper, etc. blindfold a child and give to touch each of them, explaining at the same time, what are they made of. Then give him different things and ask what material they are made. Correct toddler, if he was mistaken.
In the future, sometimes Osadchaya little man with a question: "How do you think the material from which made this thing?"